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3.10
Pr
eca
utions for
Use of File Register
s
3.10
Precautions for Use of File Registers
This section explains the precautions for use of the file registers in the QCPU and LCPU.
(1) CPU modules that cannot use file registers
The Q00JCPU and Q00UJCPU cannot use the file registers. When using the file registers, use the CPU module of other
than the Q00JCPU and Q00UJCPU.
(2) Setting of file registers to be used
When using the file registers, the file registers to be used must be set with the PLC parameter or QDRSET instruction.
(The PLC parameters of the Q00CPU, Q01CPU and LCPU need not be set since they are preset to "Use file register".
QDRSET instructions are not available with LCPU.) If the file registers to be used have not been set, normal operation
cannot be performed with the instructions that use the file registers.
Even when file registers to be used are not set in the PLC parameter, a program that uses file registers can be created. For
the CPU module other than the Universal model QCPU and LCPU, an error does not occur when that program is written to
the CPU module.
However, note that the correct data cannot be written/read to/from the file register.
For the Universal model QCPU and LCPU, an error occurs if the program where file registers are used is executed.
(3) Securing of file register area
(a) High Performance model QCPU, Process CPU, Redundant CPU, Universal model QCPU
When using file registers, register the file registers to the standard RAM/memory card to secure the file register
area.
(b) Basic Model QCPU (except Q00JCPU)
The file register area has been secured in the standard RAM beforehand. The user need not secure the file register
area.
(c) LCPU
To use the file register, secure a file register area by registering the file register in standard RAM.
The following table indicates the memories that can use the file registers in each CPU module.
: Can be registered, : Cannot be registered.
*1:
When the flash memory is used, only read from the file registers can be performed. (Write to the flash ROM cannot be
performed.)
*2:
When the E
2
PROM is used, write to the E
2
PROM can be performed with the PROMWR instruction.
*3:
Unusable for the Q00UCPU and Q01UCPU.
Remark
For the file register setting method and file register area securing method, refer to User’s Manual (Functions Explanation,
Program Fundamentals) for the CPU module used.
(4) Designation of file register number in excess of the registered number of points
(a) Basic Model QCPU, High Performance model QCPU, Process CPU, and Redundant CPU
An error will not occur if data are written or read to or from the file registers that have numbers greater than the
registered number of points. However, note that the read/write of correct data to/from the file registers cannot be
performed.
(b) Universal model QCPU and LCPU
When data are written to or read from the file registers that are not registered, an error occurs. (Error code: 4101)
Memory
High Performance model QCPU
Process CPU
Redundant CPU
Universal model QCPU (except Q00UJCPU)
Basic Model QCPU
(except Q00JCPU),
LCPU
Standard RAM
Memory card *1 *2
*3
